Organic carbonates such as the dialiphatic carbonates, aliphatic aromatic carbonates, and diaromatic carbonates are generally conventionally prepared by the reaction of phenols or alcohols with phosgene in the presence of acid binding agents such as the organic bases or inorganic bases. However, due to the toxicity of phosgene it is sometimes desirable to avoid the use of phosgene in the preparation of these organic carbonates.
Since the dialiphatic carbonates, such as the dialkyl carbonates, may be prepared from alcohols by routes other than those utilizing phosgene, i.e, catalytically from carbon monoxide and oxygen, it is possible to prepare the aliphatic aromatic carbonates and the diaromatic carbonates from these dialiphatic carbonates and phenols without using phosgene. Such phosgene free processes are disclosed in U.S. Pat. Nos. 4,045,464 and 4,182,726. These patents disclose the prepartion of alkyl aryl carbonates and diaryl carbonates from dialkyl carbonates and phenols in the presence of a catalyst which is selected from Lewis acids and compounds of transition metals.
It would, however, be most advantageous if a phosgene free process which is more effective and efficient than those presently available could be provided for the preparation of aliphatic aromatic carbonates and diaromatic carbonates from dialiphatic carbonates. It is, therefore, an object of the instant invention to provide such a phosgene free transesterification process for the production of aliphatic aromatic carbonates and diaromatic carbonates from dialiphatic carbonates.